The invention relates to a steering lock for motor vehicles in which a lock cylinder having a rotor and a stator is received in a steering lock housing having a tubular end section. A pot-shaped cap of high-strength material surrounds the tubular end section of the steering lock housing.
From German Patent Specification 2 053 775, a steering lock of this type is known which is protected from outside by a particularly stable cap and demonstrates no visible access to the interior of the steering lock. For the detention of the cap, a bolt-shaped locking element engages in an inner grooved ring of the cap. For the return guidance into an unlocking position, the locking element head in the grooved ring and the grooved ring are provided with bevels which act as guide surfaces and, when the cap is pulled off, transport the locking element into a setting displaced into the notches on the rotor. In this case, this bevel also however opens Up the possibility of violently interfering with the locking element in a locking position of the locking element by pulling powerfully upon the cap, which could then cause damage to the rotor or to the sensitive tumblers on the rotor. Even if there is a failure to pull the cap right off, the steering lock could still be damaged and any operation of the steering lock using the vehicle key rendered impossible.
An anti-theft device on a steering lock is likewise known from German patent document DE-UM 79 19 938, in which a bearing surface of the locking element, which bearing surface lies parallel to the direction of displacement, is provided on the cap groove, the configuration of the anti-theft device providing, however, an unlocking position which can only be reached using a special tool which has to be introduced from outside through a bore. It is disadvantageous in this case that any authorized person who would like, for example, to repair the lock must also be in possession of the special tool and, moreover, that the lock cylinder, which is accessible from outside through the bore, also allows the interior of the lock to be manipulated, contradictory to the protective function of the cap.
An object of the invention is to protect a steering lock of the generic type better against unauthorized tampering.
This object is achieved according to the invention by providing a steering lock for motor vehicles in which a lock cylinder having a rotor and a stator is received in a tubular steering lock housing having a tubular end section and comprising:
a pot-shaped cap made from a high-strength material and surrounding the tubular end section of the lock housing, said cap having a central access for a vehicle key, PA1 at least one locking element mounted in the steering lock housing, said at least one locking element being spring-biased in a radial outward direction and being radially displaceable between a locking position protruding into an inner ring groove of the cap to prevent axial displacement of the cap and an unlocking position, in a predetermined rotational setting of the rotor out of the inner groove of the cap, into a notch in the rotor, and PA1 a circumferential spring wire secured along a base of the inner groove, said spring wire exhibiting for each locking element a wire section which is formed out radially up to a margin of the inner groove and by virtue of which the locking element can be displaced towards the rotor and which can be bent elastically up to the base of the inner groove.
A pot-shaped cap made from a high-strength material protects the lock cylinder in the steering lock housing from non-permitted alterations to the locking state brought about by a vehicle key. This cap is fastened on the steering lock housing in such a way that, from outside and by virtue of the cap itself, no manipulation of the steering lock is enabled. For this purpose, the cap exhibits on the inside a ring groove into which there protrudes a locking element which is spring-biased in the radially outward direction and prevents axial displacement of the cap and which is mounted displaceably in the steering lock housing and, in a certain rotational setting of the rotor, can be slid into a notch in the rotor and can thereupon be moved out of the inner groove of the cap. The locking element is moved back into its unlocking position by a spring wire skirting along the foot of the inner groove, in that an elastically flexible wire section of the spring wire, which wire section is formed out in radial relief, displaces the locking element into the notch of the rotor whenever the cap is twisted. Twisting of the cap without an appropriate rotational setting of the rotor, in which the notches allow displacement of the locking elements, does not lead to an inadmissible exertion of force upon the locking element or lock cylinder, since the elastically flexible wire section is in this case elastically deformed in the direction of the foot of the inner groove by the non-yielding locking element, then stands up again in relief and is able to assume its displacement function when the rotor is twisted.
As a result of the cap being axially pressurized, no radial force is able to act upon the locking element, since the locking element exhibits, parallel with the side walls of the inner groove, supporting faces lying parallel to the direction of displacement.
In order to support the spring-biased displacement of the locking elements into their locking position, the notch in the rotor can be configured as a guiding edge for the locking element, by which the locking element, whenever the rotor is twisted by the vehicle key, is moved radially outwards into the inner groove of the cap. For this, a notch is suitable which is semi-circular in rotor cross-section and which is matched in its shape to the engagement curvatures of the locking element.
A uniform holding force for the detention of the cap on the steering lock housing is obtained in especially preferred embodiments by virtue of two radially opposing locking elements to which there are assigned two wire sections which are formed out opposite each other in relief for their displacement into the unlocking position.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.